This section provides background information related to the present disclosure which is not necessarily prior art.
Reverse total shoulder arthroplasty is one of several types of shoulder replacement surgeries. In reverse total shoulder arthroplasty, a portion of a patient's humerus and a portion of the patient's glenoid is replaced and/or augmented with implantable components. These components may include a humeral cup and a glenoid implant. Generally, the humeral cup is coupled to the humerus, replacing the head of the humerus, and the glenoid implant is installed on the glenoid. In an anatomically correct shoulder joint, the “ball” of the shoulder joint is on the humerus side of the shoulder joint. Because the glenoid implant acts as the “ball” and the humeral cup acts as the glenoid, in reverse total shoulder arthroplasty, the “ball” is on the glenoid side of the shoulder joint. In other words, the relationship between the components in the surgically created shoulder joint is opposite that of the anatomically correct shoulder joint.
Because anatomy varies among patients, a surgeon must choose a glenoid implant that fits the patient undergoing surgery. To determine proper fit, a glenoid trial is used. Before the glenoid implant is installed, the surgeon positions the glenoid trial on a baseplate assembly that is installed on the glenoid. An adapter assembly may be used to couple the glenoid trial to the baseplate assembly where a threaded fastener attaches the glenoid trial to the adapter assembly. An apical opening is provided in the glenoid trial to receive the threaded fastener and to provide access to the head of the threaded fastener. Once the glenoid trial is installed on the adapter assembly and is positioned on the baseplate assembly, the surgeon trials the surgically created shoulder joint by moving the humerus through a range of motion. Such trialing allows the surgeon to evaluate the fit and function of the glenoid trial. If trialing is unsatisfactory, the surgeon must remove the glenoid trial from the baseplate assembly and repeat the process with another glenoid trial that has a different size and/or shape. This process continues until a satisfactory glenoid trial is found.
Once a satisfactory glenoid trial is found, the surgeon removes the glenoid trial from the baseplate assembly and reads the position of the glenoid trial, which is measured relative to the adapter assembly. The surgeon then selects a glenoid implant that matches the size and shape of the glenoid trial that is selected during the trialing and replicates the position of the glenoid trial relative to the adapter assembly when constructing the glenoid implant. The glenoid implant is then installed on the baseplate assembly and is positioned in contact with the humeral cup to complete the assembly of the surgically created shoulder joint.
While known implants for reverse total shoulder arthroplasty and related implantation methods may have proven to be generally effective, a continuous need for improvement over the pertinent art remains.